DESCRIPTION There is a fundamental gap in understanding the lack of complete benefit after in-utero spina bifida repair where fewer than half of the patients show improvement in spinal cord function. The long-term goal of this project is to incrementally improve the neurological outcomes of affected children through the regenerative repair of the defect site. The overall objective of this application is to determine whether the use of cryopreserved human umbilical cord (HUC) for in-utero spina bifida repair reduces inflammation and scar formation at the repair site, and thus improves neurological outcomes in a sheep model. The central hypothesis is that HUC compared to conventionally used methods improves the function of the spinal cord at and below the defect site and reduces the surgical sequelae of scar formation in a surgical spina bifida model in a pregnant sheep. This hypothesis has been formulated by preliminary data produced in the applicant?s laboratory. HUC is FDA approved for ophthalmological diseases and has an active component, heavy chain hyaluronic acid/pentraxin3, which demonstrates anti-inflammatory and anti-scarring properties. The rationale for the proposed research is that exploration of the properties of HUC as a regenerative patch in in-utero spina bifida repair has the potential to immediately translate into humans to improve outcomes in spina bifida, which affects over 4000 live births annually in the United States. The hypothesis will be tested by pursuing two Specific Aims in a sheep model: 1) Compare histological, radiological and clinical outcomes of in-utero repair using HUC vs. acellular dermal matrix (ADM) based patch repair for the skin closure in large spina bifida defects, and 2) Compare similar outcomes using HUC as a dural patch under the primary skin closure vs. multilayered closure. Using the established surgical spina-bifida model in pregnant sheep that generated our preliminary data, Specific Aim 1 seeks to quantitatively assess inflammation, scar formation using histology and advanced magnetic resonance imaging, and neurological outcomes using the validated Texas Spinal Cord Injury Scale and bladder control in lambs repaired with HUC compared to ADM. In Specific Aim 2, dural substitute with a HUC placed between the skin closure and neural placode or conventional multilayered closure will be used in the same model as above, and assessments will be performed similarly to Aim 1. The approach is innovative, as it departs from the status quo by utilizing the naturally occurring regenerative properties of HUC to improve healing of in-utero spina bifida repair to reduce long-term neurological sequelae. The proposed research is significant because it is expected to vertically advance and expand the benefits of in-utero repair of spina bifida including facilitating the minimally invasive repair to reduce maternal risks associated with the large uterine incision needed for the current approach. Ultimately, such knowledge has the potential to find newer approaches to the treatment of other congenital anatomical birth defects such as cleft lip/palate, gastroschisis, and diaphragmatic hernia.